The present invention relates to a system and a method for separating a hydrocarbon containing material such as crude oil from water.
Water effluent from many dehydration and dewatering processes contain crude oil or other hydrocarbon containing materials, either in free form or dispersed in the water. It is necessary to separate the crude oil or other hydrocarbon containing material from the water if the water is to be re-used. A conventional system for treating water effluent containing crude oil from a water dehydration system is shown in FIG. 1. As shown therein, water coming from a dehydration tank 10 is drained into a separator 12 wherein crude oil, or droplets of crude, having a size greater than 150 microns is separated. The system also includes a mechanical separation device 14 formed by a series of plates which gravitationally separate those droplets with a size between 50 and 150 microns and a gas or air floatation device 16 wherein droplets with a size between 20 and 30 microns are separated. Still further, the system includes a final stage filter 18 filled with sand or synthetic material to obtain water with a quality suitable for re-use.
This type of system and process is expensive and time consuming. There remains a need for a system and a process which is cheaper and more efficient. There also remains a need for a process which lends itself to the treatment of water effluents containing a wide range of crude oil or other hydrocarbon containing materials.